What’s the best piece of relationship advice you have?

I’m 21 and never been in a relationship and am just curious to know any relationship advice.

Whats the best piece of relationship advice you can give me?

I am 17 years old and I have been in a relationship with my partner for 9 months. What advice can you give me to keep it afloat and make it last? Experience not nessicary :) Wisdom comes from all walks.